Safety mechanism for explosively actuated tools



R. TEMPLE SAFETY MECHANISM FOR EXPLOSIVELY ACTUATED TOOLS Filed June 22,1948 JNVENTOR. P055??- 7Z=MPLE BY /mm [Q w v his Aug. 16, 1949.

"nu-LE Patented Aug. 16, 1949 Nmzo srras SAFETY MECHANISM FOREXPLOSIVELY ACTUATED TOOLS Application June 22, 1948, Serial No. 34,542

7 Claims. 1

This invention relates to safety mechanism for explosively actuatedtools that may be used for driving studs and the like, and moreparticularly to such tools which can not be discharged accidentally.

In one type of driving tool the explosive cartridge that furnishes thedriving power is detonated by pushing the barrel back into the tool topress the cartridge against a stationary firing pin. If the barrelshould be pushed back accidentally, as might happen if the tool weredropped and landed on either end, the cartridge would strike the firingpin and the stud or other projectile would be driven out of the barrel.That would endanger any nearby persons.

It is among the objects of this invention to provide a sliding barreltype of explosively actuated driving tool which can not be dischargedaccidentally, which requires a special manipulation by the operatorbefore the tool is in condition to be fired, and which automaticallyreturns to a non-firable condition when the tool is released.

In accordance with this invention a breechblock is slidably mounted in abarrel guard in the form of a sleeve projecting from the front of astock that can be held in the hand. The breechblock, which has an axialpassage through it, is urged forward in the sleeve by a spring.Detachably connected with the front end of the breechblock is a barrelwhich projects from the guard. The stud is provided with a threadedopening in line with the breechblock passage, and a firing pin isthreaded in that opening. The pin normally is retracted far enough tokeep its front end from projecting through the breechblock passage andinto engagement with a cartridge, pressed against the front of thebreechblock, in case the barrel accidentally pushes the breechblockrearward in the sleeve to firing position. In order to permit the toolto be discharged, there is a turning member for the pin which is adaptedto be turned manually in one direction for screwing the pin forward inthe threaded opening of the stock far enough that the pin will projectthrough the breechblock passage when the block is pushed back to firingposition. When the turning member is released, it is automaticallyturned in the opposite direction to return the pin to its retractedposition. This preferably is done by means of a spring. It also isdesirable to provide a stop for limiting the distance that the turningmember can be turned in either direction. To prevent the tool from beingused as a weapon with a stud serving as a bullet, the barrel normallyprojects from the sleeve a distance not materially greater than thedistance between the forward and rearward positions of the breechblockin the sleeve. This prevents a person from holding the stock in one handand pulling the barrel back in the guard with the other hand, as he willnot be able to hold onto the barrel and pull it back far enough into theguard to cause the cartridge to strike the firing pin.

The preferred embodiment of this invention is illustrated in theaccompanying drawings in which Fig. ,1 is a plan view of the tool; Fig.2 is a central longitudinal section thereof taken on the line II-II ofFig. 1; and Fig. 3 is a transverse section taken on the line I[I]II ofFig. 2.

Referring to Figs. 1 and 2 of the drawings, the stock is in the form ofa D-handle provided with a hand grip l. Opposite the grip the stock hasa forwardly projecting portion 2 extending into the rear end of a sleeve3 that is held in place by a screw d and forms a barrel guard. Slidablymounted in the rear end of the sleeve is a breechblock 6 that has a deeprecess 7 in its rear end for receiving a coil spring 8 that urges theblock away from the stock. Forward movement of the breechblock islimited by a cap screw projecting from the top of the block into a slotl0 extending lengthwise of the sleeve. This slot may be covered by anameplate H or the like. The front end of the breechblock is providedwith a short threaded recess l2 in which the rear end of a barrel I3 isscrewed. The rear end of the axial bore it through the barrel is adaptedto receive a cartridge IS, the rim of which is clamped between the rearend of the barrel and the breechblock. Preferably, the front end of thcartridge is crimped over a forwardly tapered rear portion of a pistonmember I? that is frictionally connected to the rear end of a stud 88for supporting it centrally in the barrel. The stud is shaped for thepurpose for which it is intended, the one shown having a threaded rearend and a knurled central portion of smaller diameter to hold it in thematerial into which the stud is driven by the tool. The front end of thebarrel is formed by a muzzle cap 1 9 provided with a recess for holdinga metal washer 2i that is carried out of the cap by the stud. The borethrough the cap is slightly smaller than the one through the rest of thebarrel so that piston II will be stopped by the cap as the stud leavesthe barrel. Barrels with different size bores for receiving studs ofdifferent diameters are interchangeable with the one shown. When abarrel is being screwed into or out of the breechblock,

the latter is prevented by cap screw 9 from rotating.

The breechblock is provided with an axial passage 22 through which afiring device can be projected for detonating cartridge IS. The firingdevice is in the form of a firing pin mounted in the stock, anddischarges the cartridge when the barrel is pushed back a predetermineddistance in barrel guard 3. The guard has a vent 23 to permit air toescape from behind the breechblock as the latter moves rearward in theguard. It is a feature of this invention, however, that simply pushingthe barrel back in the guard will not detonate the cartridge, wherebyaccidental discharge of the tool is avoided. With this invention it isfirst necessary to move the firing pin forward from an inoperative to anoperative position. Accordingly, the firing pin has a point member 24integral with the front end of a threaded shank 25 that registers withthreads formed in the wall of an opening 26 extending through the stockportion 2 in line with breechblock passage 22. The pin projects fromboth ends of the stock opening; the front portion of the pin beingslidably mounted in a guide mem-, ber 21 engaging the rear end of spring8. Its inoperative position is one in which the pin is retracted farenough so that even if the barrel is pushed back in the guard sleeve asfar as it will go, the point 24 will not project through the breechblockpassage. In order to move the firing pin forward into firing position, alever or arm 28 is rigidly mounted on its projecting rear end so that byswinging the arm to turn the pin, the pin is screwed forward through thestock far enough to be engaged by the cartridge when the barrel ispushed back. The position to which the arm is swung manually is shown inbroken lines in Fig. 3. A stop member 29 is screwed into the stock inthe path of both ends of the arm to limit the distance that the arm canbe turned in either direction to only that necessary for moving the pininto and out of firing position. Although a single thread may be used toconnect the shank of the firing pin to the stock, a multiple lead threadis preferred because it permits a greater forward movement of the firingpin to be obtained for a given rotation of the pin.

An important part of the invention is that the moment the operatorreleases arm 28, the pin automatically is returned to its retractedinoperative position. This is accomplished by a spring 3| coiled aroundthe rear end of the firing pin shank in front of the arm. One end of thespring is anchored in a slot 32 in the stock, while the other endprojectsinto a hold 33 in the arm. This torsional spring is put undersuch tension when the arm is swung manually to firing position that itwill automatically swing the arm back to its original position, shown infull lines in Fig. 3, when released.

Another feature of this invention is that the barrel normally projectsfrom its guard a distance substantially equal to, or not materiallygreater than, the distance that the breechblock travels in the sleeve.Consequently, very little of the barrel projects from the guard at themoment the tool is fired. This prevents a person from pushing the barrelback in the guard by hand and thereby using the tool as a weapon withthe stud serving as a projectile.

It will be seen that the operation of this tool is as follows. After thebarrel has been loaded with a stud and cartridge and has been screwedinto the breechblock, the front end of the barrel is placed against theobject into which the stud is to be driven. One hand can grip the barrelguard while the other hand grips the hand grip I. A thumb or finger ofthe latter hand then is used to swing arm 28 clockwise as far as it willgo. This screws the firing pin ahead into operative position. While thearm is held in this position the handle is pushed forward to push thebarrel and breechblock back into the guard sleeve as far as they willgo. This causes the cartridge to strike the firing pin and bedischarged, thus driving the piston and stud forward in the barrel. Thepiston is stopped by the muzzle cap l9, and the shock separates thepiston from the stud which enters the object against which the barrelhas been pushed. The arm then can be released, but torsion spring 3|will return it to its original position in which the firing pin will beretracted far enough so that it can not detonate the next cartridgeuntil the arm again is swung by the operator clockwise against the stop29. In this way a safety is provided for the tool which prevents it frombeing discharged accidentally.

If the tool is droppedand strikes on either end so that the barrel isimpelled inward, the cartridge will not strike thefirin pin because itis retracted. Likewise, the threaded connection between the firing pinand stock prevents the pin from being impelled forward to operativeposition by inertia or jarring.

According to the provisions of the patent statutes, I have explained theprinciple of my invention and have illustrated and described what I nowconsider to represent its best embodiment. However, I desire to have itunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically illustrated anddescribed.

I claim:

1. An explosively actuated driving tool comprising a stock, a sleeveprojecting from the front of the stock, a breechblock slidably mountedin the sleeve and provided with an axial passage therethrough, a springurging the breechblock forward in the sleeve, a barrel detachablyconnected with the front end of the breechblock and projecting from thesleeve, the stock being provided with a threaded openin in line withsaid passage, a firing device threaded in said opening and having apoint member projecting from its front end, said device normally beingretracted in said opening to keep said point member from projectingthrough said passage when the breechblock is accidentally pushedrearward in the sleeve by the barrel to firing position, a turningmember for the firing device adapted to be turned manually in onedirection for screwing said device forward in said opening apredetermined distance so that said point member will project throughsaid passage when the breechblock is in said firing position, and meansoperative automatically when the turning member is released for turningsaid device in the opposite direction to return it to its retractedposition, whereby a safety is provided for the tool.

2. An explosively actuated driving tool comprising a stock, a sleeveprojectin from the front of the stock, a breechblock slidably mounted inthe sleeve and provided with an axial passage therethrough, a springurging the breechblock forward in the sleeve, a barrel detachablyconnected with the front end of the breechblock and projecting from thesleeve, the stock being provided with a threaded opening in line withsaid passage, a firing pin threaded in said opening and normallyretracted to keep its front end from projecting through said passagewhen the breechblock is accidentally pushed rearward in the sleeve bythe barrel to firing position, a turning member for the pin adapted tobe turned manually in one direction for screwing the pin forward in saidopening a predetermined distance so that the pin will project throughsaid passage when the breechblock is in said firing position, and aspring operative when the turningmember isreleased for turning the pinin the opposite direction to return it to its retracted position,whereby a safety is provided for the tool.

3, An explosively actuated driving tool comprising a stock, asleeveprojecting from the front of the stock, a breechblock slidably mountedin I the sleeve and provided with an axial passage therethrough, aspring urging the breechblock forward in the sleeve,.a barrel detachablyconnected with the front end of the breechblock and projecting from thesleeve, the stock being provided with a threaded opening in line withsaid passage, a firing pin threaded in said opening and normallyretracted to keep its front end from projecting through said passagewhen the breechblock is accidentally pushed rearward in the sleeve bythe barrel to firing position, a turning member for the pin adapted tobe turned-manually in one direction for screwing the pin forward in saidopening a predetermined distance so that the pin will project throughsaid passage when the breechblock is in said firing position, and aspring connectedto the turning member for turning it in the oppositedirection to return the pin to its retracted position, whereby a safetyis-provided for the tool.

4. An explosively actuated driving tool comprising a stock, a sleeveprojecting from the front of the stock, a breechblock slidably mountedin the sleeve and provided with an axial passage therethrough, a springurging the breechblock forward in the sleeve, a barrel detachablyconnected with the front end of the breechblock and projecting from thesleeve, the stock being provided with a threaded opening in line withsaid passage, a firing pin threaded in said opening and normallyretracted to keep its front end from projecting'through said passagewhen the breechblock is accidentally pushed rearward in the sleeve bythe barrel to firing position, a turning member .for the pin adapted tobe turned manually in One direction for screwing the pin forward in saidopening a predetermined distance so that the pin will project throughsaid passage when the breechblock is in said firing position, a stoplimiting the distance that said member can be turned in said direction,and means operative automatically when the turning member is releasedfor turning the pin in the opposite direction to return it to itsretracted position, whereby a safety is provided for the tool.

5. An explosively actuated driving tool comprising a stock, a sleeveprojecting from the front of the stock, a breechblock slidably mountedin the sleeve and provided with an axial passage therethrough, a springurging the breechblock forward in the sleeve, a barrel detachablyconnected with the front end of the breechblock and projecting from thesleeve, the stock being provided with a threaded opening in line withsaid passage, a firing pin threaded in said opening and projectingthrough said passage when the breechblock is accidentally pushedrearward in the 'sleeve by the barrel to firing position, the rear endof the pin projecting from said opening, an

arm rigidly mounted on said projecting rear end of the pin for turningit in one direction in order to screw the pin forward in said opening apredetermined distance so that the pin will project through said passagewhen the breechblock is in said firing position, a spring connected tosaid arm for turning it in the opposite direction to return the pin toits retracted position, and a stop for limiting the distance that thearm can be turned in either direction.

'6. An explosively actuated driving tool comprising a stock, a sleeveprojecting from the front of the stock, a breechblock slidably mountedin the sleeve and provided with an axial passage 'therethrough, a springurging the breechblock forward in the sleeve, a barrel detachablyconnected with the front end of the breechblock and projecting from thesleeve, the stock being provided with a threaded opening in line withsaid passage, a firingpin threaded in said opening and normallyretracted to keep its front end from projecting through said passagewhen the breechblock is accidentally pushed rearward in the sleeve bythe barrel to firing position, the barrel normally projecting from thesleeve a distance substantially equal to the distance between theforward and rearward positions of the breechblock in' the sleeve, aturning member for the pin adapted to be turned manually in onedirection for screwing the pin forward in said opening a predetermineddistance so that the pin will project through said passage when thebreechblock is in said firing position, and means operativeautomatically when the turning member is released for turning the pin inthe opposite direction to return it to its retracted position, whereby asafety is provided for the tool.

7. An-explosively actuated driving tool comprising a stock, a sleeveprojecting from the front of the stock, a breechblock slidably mountedin the sleeve and provided with an axial passage therethrough, a springurging the breechblock forward in the sleeve, a barrel detachablyconnected to the front end of the breechblock and projecting from thesleeve, said barrel being adapted to receive an explosive cartridge andto clamp its rim between the adjoining ends of the barrel andbreechblock, the stock being provided with a threaded opening in linewith said passage, a firing pin threaded in said opening and normallyretracted to keep its front end from projecting through said passagewhen the breechblock is accidentally pushed rearward in the sleeve bythe barrel to firing position, a turning member for the pin adapted tobe turned manually in one direction for screwing the pin forward in saidopening a predetermined distance so that the pin will project throughsaid passage when the breechblock is in said firing position, and meansoperative automatically when the turning member is released for turningthe pin in the opposite direction to return it to its retractedposition, whereby a safety is provided for the tool.

ROBERT TEMPLE.

No references cited.

